Internal combustion engines are widely used for driving a variety of vehicles. Internal combustion engines come in a variety of configurations, which are typically aptly named for the particular orientation or arrangement of the reciprocating pistons and cylinders in the engines. One example of an internal combustion engine is a “V” type engine, in which the “V” refers to the arrangement of the cylinders in rows that are angled relative to each other to form a V shape. Another type of internal combustion engine that is most relevant to the invention is a barrel-type engine.
The barrel engine includes a plurality of cylinders and pistons arranged in the form of a “barrel” in which their axes are parallel to each other and typically arranged along a circle concentric with the drive shaft. Power is transmitted from the reciprocating pistons to a cam plate via a roller or bearing interface. The cam plate's nominal plane is perpendicular to the piston axes and attached to the drive shaft for movement therewith. The cam plate also has a generally sinusoidal shape, so that the axial reciprocal movement of the pistons causes rotational movement of the cam plate and drive shaft.
The intake and exhaust valves of the barrel engine may be actuated by cams that are driven by the drive shaft. In conventional designs, the cams are integrally formed with the drive shaft in a casting and/or milling processes, which results in relatively high manufacturing costs. It is, therefore, desirable to provide an improved drive shaft design that is less expensive to produce than conventional drive shaft designs, and/or provides other benefits.